The post you are reporting:
" Ill conceived and expensive to administer"
This may certainly be true, but not the fault of any potential or actual claimant.
" going unclaimed by many people"
This is easy to say, but I doubt that any increase in the claimant numbers would lessen the impact of the first two points above, it is more likely that many more enquire of the possibility of claiming only to learn that it is not for them.
"all deficit spending, [holding down wages]"
I suppose it is a matter of taste as to how many eggs a pudding requires;one persons too many can be another's too few. Nonetheless, it IS deficit spending pretty much only because you say it is. No employer while in the process of 'down sizing' concerns themselves with any concomitant increase in the deficit spend. After all, their efforts are expended in reducing their contribution to Public Coffers, leaving only energy enough to complain. [Barry, much of the argument you use comes across as a process of petulance. Can it be that wages are artificially low because Governments are plain silly in their efforts at boosting income through Public Spending? Are employers to gather their toys from outside their pram, and release these reserves of underpaid wages just as soon as their employees are homeless and in want of sustenance?]
NEWS FLASH!
Should (and I mean 'if') employers increase wages, lo and behold, they shall discover that fewer and fewer of their employees will be in receipt of Working Tax Credits.